Metal-edge filter stack



Feb. 17, 1948. 'P.HE| =TLE 2,436,108

METAL-EDGE FILTER STACK Filed March 9, 1944 3 Sheets-Sheet 1' Feb 1 ms.

FIG. 9

P. HEFTLER METAL-EDGE FILTER STACK Filed March 9, 1944 *3 Sheets-Sheet 2 DIRTY LIQUID 65 P. HEFTLER METAL-EDGE FILTER STACK Feb. 17, 1945.

Filed March 9, 1944 3 Sheets-Sheet 3 Patented Feb. 17, 1948 METAL-EDGE FILTER STACK Paul Heftler, Windsor, Ontario, Canada Application March 9, 1944, Serial No. 525,750

8 Claims. (01. 210-469) The invention described below andillustrated in the accompanying drawings is a metal-edgefilter stack of the general type shown in U. S. Patent No. 1,641,485. In all of the filter stacks of this general type that were made before this invention and that were made of metal of a single thickness without coining or otherwise changing the thickness of the metal, there have been two different patterns of, washers, the two patterns being either stars and wheels, as in the filter stack shown in Patent No. 1,641,485, or else clover-leaves with difierently orientedcentral aligning holes, as in the filter stack shown in U. S.-Patent No. 1,694 939. The use of two (iii-- ferent patterns of washers-was necessary in order that'the rim parts'of similar washers would be spaced apart by the intervening dissimilar washer and so that the stacking of the washers could be done automatically, as shown in U. S. Patent No. 1,694,939 with a die set of the type shown in U. 8. Patent No. 2,204,592. Until the invention described below was made, that method of stacking was the most economical way of making metal-edge filter stacks.

One disadvantage of the method of stacking just referred to is that it requires difierent dies to produce the two different patterns of washers that are necessary, and the dies are quite expensive because they must be made very accurately in order to cut cleanly the thin metal of which the washers are made. The die cost forms a large part of the cost of each filter stack,

and this is especially true-of the larger sizes of filter stack which are not made inlarge quantities. p

- The filter stacks described below as examples of the invention are so designed that all of the washers of each are identical and have the same side up, which enables them to be made and stacked by a die'set having only a, single pattern die and therefore costing a good deal less than the type of die set shown in Patent No. 2,204,592

Having the same side of all the "washers up is important because, although a-filter stack can be made with all of the washers like oneof the washers showninPatent No. 1,694,939-by turnmg every other washer upside down, it cannot be done in any simple die set. The invention, therefore, is a metal-edge filter stack of the type formed by washers of thin sheet metal of uniform thickness and in which the Washers are all alike and have thesame side up.

This invention was made a considerable time before the filing of this application, and this.

n: earlier copending applications,

Serial Nos. 129,326, now abandoned, 337;.406, now Patent No.

2,260,899, and 361,430, now abandoned, has; the filing date (March 6, 1937) of the earliest of those applications as its efiective date forthev invention.

- The drawings Figure 1 is a diagrammatic perspective view of one form of die set, having only one patterndie, for making the new'type of filter stack;

Figure 2 is a perspective view of a part of thenew type of filter stack, the particular filter stack shownin this figurebeing slightly different from the one which is being shown in the process of beingassembled in Figure 1;

Figure 3 is a plan view of one of the washers of the filter stack shown in Figure 2;

Figures 4, 5 and 6 are plan views of other washers for other filter stacks made and assembled in the same way as shown in Figure 1;

Figure '7 is a plan view showing how, with a die set a little different from the one shown in Figure 1, the washers oi the new type of filter stack can be cut out of the stock with less waste than,

the washers of the old; V

Figure 8 is an isometric viewlillustrating the making of another form of the invention; 2

Figure 9 is an isometric view, partly in section;

showing a complete filter stack of the type shown in Figure 8 assembled in a filter;

Figure 10 is an isometric view, partly brokenaway and on an enlarged scale, of four washers o the filter stack shown in Figures 8 and 9:

Figure 11 is a plan view of one of the washers of the filter stack shown in Figures 8 to 10;

vFigure 12 is an isometric view illustrating the making of still another form of the invention; and p l Figure 13 is a plan view of one of the washers of the filter stack shown in Figure 12.

The filter stack One of the many possible forms of filter stackwhich may be made according to this inventionis illustrated-in Figure 2, which shows the lowerpart of the stack. The stack is assembled on ahexagonal stem 36 riveted to a thick solid bottom washer 31, and it includes a large number of thin;

clover-leaf washers 40, whose shape is shown in plan in Figure 3. As may be seen from this application, being a continuation in part of my '55 figure, each clover-leaf washer has a central portion with a hexagonal hole 4|,six equally spaced arms 38 radiating out from the central portion, and three curved sectors or rim portions 39 joining the ends of successive pairs of arms.

All of the clover-leaf washers are alike, but each one is turned one sixth of a turn from the position of the washer immediately under it so that, although the arms 38 of each washer lie directly on top of the arms 38 of the washer just below, the rim sections 39 of each washer extend across the open gaps between the lobes or leaves of the washer just below. Thus, the rim sections 39 of the first, third, fifth, seventh,,etc., washers lie one above the other but are spaced apart by the arms of the second, fourth, sixth, etc., washers so that narrow slits or slots 48 are left between them. Similarly, the rim sections of the second, fourth, sixth, eighth, etc, washers lie one above the other and are spaced apart by the arms of the third, fifth, seventh, etc.,' washers soi'that narrow slits or slots 48 are left between them also.

inFigure 2, all'the particles of dirt too large to' pass through thes lots are caught on the outside of V the filter stack. The liquid which flows through the slots' 48 'then fiows upand out through vertical passages 49 which are formed by the-holesfin the lobes ofalternate washers lining up with the gaps between the lobes of the other washers. The lower ends of the passages are closed by the solid bottom washer 31, and theupper ends of the passages connect with the outlet passage in the filter. head, as shown in Patent Noi 1,641,4850! substantially as shown in Figure 9.

Thedie .set for making the filterstack .One formbf die set formaking and assembling washers of the general typeshown in Figures 2 and 3 into a stack is shown in Figure 1. This form of die sethasa dieflholder l and a punch holder] adapted to be secured to "the-ram and the bolster of a conventional-punch press. They are guided with respect to each other by conventional guide posts 3 secured to the die holder l and slidingjinholes 4 -in.the punch holder 2.

The die h'older i has apattern diev 5 and a blanking die 8.set.into it in the usual-manner, and the punch holder 2 carries a pattern punch 5 and a blankingv punch 1. arranged to cooperate with the dies B and 8 to produce the washers 9 from the strip of stock Ill. Each washer 9 is similar to the washers 40 shown in Figures 2 and 3, having six radial arms 3|. joined together in pairs by rim portions l4. However, in the washer formed by this particular die set, the central hole ll, insteadof being hexagonal, is round with two lugs l5 projecting in fromopthefinalassembly of the filter stack is made as shown inUI. S. Patent No. 1,977,174.

' As each washer 9 is blanked out, it falls down onto a stem' l2 shaped to fit the central hole ll inthe washer and having its upper end tapered so that the washers will fallonto it more easily. Since the lugs in the holes in the washers are directly opposite each other and the grooves in the stem I2 for receiving the lugs l5 are also directly opposite each other, each washer can fit 'Two thousandths is a commonposite sidesl With this form of central hole Q on the stem l2 in two positions a half a turn from each other. Alternate washers are placed in alternate positions by rotating the stem (2 half a turn just before each washer is placed on it.

The mechanism for rotating the stem l2 may be of any convenient type, such as a Geneva motion, but, for the purpose of illustration, I have shown gears 22, 23 and 24 driven through a ratchet 25 and pawl 26 from a connection 2'! to the punch holder 2. This mechanism rotates, step by step, a shaft 2| upon which is mounted a cam 25 and the stem I2. The cam 28 is provided with two diametrically opposed notches 30 for receiving an .indexing roller 3| carried by a swinging arm' 32. The arm 32 is mounted on a stationary pivot 33" and is pressed towards the cam 20 by a spring 34 reacting on a fixed abutment 35; This presses the roller 3! into the notch 35 and ensures that the cam 20 and the stem I2 stop in the correct orientation after each half turn.

Other forms of the invention washer just below. it. Other die sets than the one.

shown in Figure l can-be used to form and assemble the washers. For example, the pattern punch and die of the die set can be made to punch out only the holes in the washer without punching out the gaps between the lobes, and the blanking punch and die can be made to form the entire outline of the washer. If this is done, the

washers 40 can be arranged to be punched out much closer together from the stock 10, as shown in Figure 7, thus efiecting a material saving of stock.

Another .form of the invention is shown in Figures 8 to 11. In making this, a strip of stock 50 of the desired thickness,such as .002 inch, is passed through several successive stations A, B, C, and D, at each of which a part of the process of making each washer is carried out. 'At the first station A, an irregular hole 5| is punched out. The hOle 5| is approximatelyroundbut it has six tongues 52 projecting in towards its center, and it has a pair of notches 53 at opposite sides. It is concentric with a circle 54 which marks the. future outer edge of the finished washer.

At the second and third stations B and C, the six tongues 52 are first bent straight up and then are bent down flat on top of the strip 50 so that, at each tongue, there is a double thickness of stock. At the-fourth station D, the completed washeris blanked outof the strip 50 and is stacked on topof previously formed washers 55. This forms a stack! which is mounted on a:

keep the washers from'sliding off when. the filter. stack is removedirom the .filter head 62 to be cleaned.

Apart from the filter stack 6 l,.the filter shown in-Figure 9 isof the standard type that has been in use for many years. It comprises a head 62 having a fiat recessed seat 63 on its under side. The top washer 58 ofthe filter stack fits against the central part of the seat 63, and a glass bowl or jar 64 and a gasket 65 fit up against the outer part of the seat 63 around the filter stack. The glass .bowl 64 is held in place by a stirrup, not shown in the drawing, that hooks under it and that has. a tightening screw fitting into a recess 66. on the top of the filter head 62 for pulling the glass bowl tightly up against the gasket 65. The filterhead is formed with an inlet passage 61, that opens down into the space between the glass bowl 64 and the filter stack 6 I, and with an outlet passage 68 that leads from the center of the filter stack 6|, so that liquid passing through the filter must pass through the filter stack, as shown by the arrows in Figures 9 and 10.

The washer'for another form of the invention is shown in Figures 12 and 13. The chief difference between this washer l5 and the washers shown in Figures 8 to 11 is that the washers 15 have a centeror hub 16 joined by three spokes 1! to the rim 18 of the washer instead of having notches on the inner edge of the rim. The hub 16, has a hexagonal hole 19 which fits on a hexagonal stem like the stem 5| of the filter stack shown in Figure 2. The spacing of the washers I5 is provided for by the folded-over tongues 80, as in the form of the invention shown in Figures 8 to 11'.

The; washers 15 are formed in practically the same way as the washers 55 shown in Figures 8 to 11,'the on1y difference being that, at the first station E, a pattern of four holes 19, 8|, 8| and 8|, instead of the single hole 5|, is punched out to'form the hub" and the three spokes Tl. At the other stations F, G, and H, the same operations are performed as atthe corresponding stations B, C, and D in forming the washer 55.

sitions in' which each piece can fit on-the" stem having anangle between them that is equal to or is an odd multiple of the angle between two successive'arms, and the pieces being arranged on the stem alternately in one position and then in the other so'that the arms, of each piece lie directly on top of the arms of'the pieces below and leave continuous longitudinal passages in the stack and so that the gaps between the curved parts of each'piece lie between the curved part of the pieces just above and below, the gaps thus providing thin slots connecting the outside of the stack to the longitudinal passages in-the stacki and-permitting liquid to flow while stopping par 5. ticles of dirt.

2. A filter stack comprising a central hexagonal vertical stem and a plurality of superposed identical washers mounted on said stem with the same side of all of the washers facing up, each of the washers being formed of thin sheet metal of univ form thickness and having a central portionwith Theiprocess and the apparatus for-making the filter stacks shown in Figures 8 to 13 are more fully described, and the process is claimed, in my Patent No. 2,260,899, entitled "High speed method of making metal-edge filters, and issued on October 28, 1941.

While only a few forms of the invention have been shown and described. it will be obvious from these that the invention can be carried out in many other ways. The invention therefore includes not only these particular filters but any others which fall within the terms of any one of the following definitions of the invention.

claim:

1. A metal-edge filter stack comprising a plurality of thin superposed identical pieces threaded on a central stem and having the same side up, the stem and the holes in the pieces through which the stem passes being shaped so that each piece could fit on the stem in two angularly different concentric positions and cannot rotate on the stem, each piece having a central part and arms radiating from the central part and curved parts joining the'ends of the arms, the central part being like the hub of a wheel and having the hole through which the stem passes, the arms being like the spokes of a wheel and being even in number and evenly spaced, the curved parts being like parts of the rim of a wheel but there being only half as many curved parts as there are arms, the curved parts being arranged evenly around the piece so that they alternately join arms together and leave gaps between them, the two poa hexagonal hole receiving and fitting said stem to prevent rotation and transverse sliding of the washer relative to the stem and the other washers, six equally-spaced radially-extending supportingand-spacing portions connected to said central portion, and curved slot-defining portions extending between said supporting-andespacing portions, all'ofthe slot-defining portions having their outer edges lying at the same distance from the center of the stem and forming filtering areas on a cylindrical surface, and each of the slot-defining portions being spaced from the adjacent slot-defining portion of another washer a distance equal to the thickness of said thin metal whereby thin slots are provided in said filtering areas,

3. A filter stack comprising a central vertical stern of non-circular cross-section and a plurality of superposed identical washers mounted on said stem" with the same side of all of the'washers facing up, said washers being formed of thin sheet metal of uniform thickness and having inner edge portions fitting said stem to prevent rotation and transverse sliding of said washers relative to said stem and to each other, each of said washers comprising radially extending supporting and spacing portions and also slot-defining por- 4 tions extending annularly between said supporting and spacing portions. all of said slot-defining portions having their outer edges lying at the same distance from the center of said stem and forming filtering areas on a cylindrical surface, and each of said slot-defining portions being spaced from a similar slot-defining portion of another washer a distance equal to the thickness of said thin metal to provide slots in said filtering areas.

4. A filter stack comprising a plurality of superposed identical washers and means extending through said washers and engaging non-concentric inner edge portions thereof for preventing rotation and transverse sliding of said washers re ative to each other, each of said washers being formed of thin sheet metal of uniform thickness and comprising radially extending spacing portions and also slot-defining portions extending annularly between said spacing portions, the outer edges of said slot-defining portions lying on and defining portions of a cylindrical surface, and each of said slot-defining portions of one washer being spaced from the adjacent slot-defining portion of a similar washer by interposed spacing portions whereby thin filtering slots are provided in said portions of said cylindrical surace.

521m filterncomprising-ia stack aotfflat pieces 101': 5- thin sheet' '"meta;r.:: 11.= alike and .ithreaded :npon-na-z: centralistemsthe astem andsthe holes-inrthepieces through :WhiChIthe =stemt13asses being shaped so 1" 8 side i'acingaup andJmeans' extendingizthrough sald washers and: engaging non-: concentric dnnenedg'e portions whereof? for: preventing 1 rotation :and transverse 'slidin'gsof saidwashers relative to 'each thetsfih'e spieizescan fition" the: steminrtwo 'posi 6 zother, each; offsaidz washers beingfiormed ot-thintions'zand :cannot" rotateiaupom :it; each rnpieceu' of: sheet; metal Fhavi-ngran; evenzxnumber: 'of ievenly' spaced=: arms radiating "from; 1a, central part "like 1: thesspokesiziof1a:iwheekzandshalving; arms forming sheet metalzof uniform:thicknessiandscomprising radially extendingspaclng portionsand also slot defining." portions "extending annularly between said r spacing *portionsrxthe :outer edges: of -2sald 1 pairs withrthe outer tends OfiLithBiaJmS'ZOf each:10%slotedefiningportions lying onandadefinlng por pair joined byg a:portion :lik arcpart'of a rim of a. i wheel,thereflaeinggaps-hetweemtheendsiof sue-1: cessive axmsiwwhich,zdo'znot 'fornr: pairs; the two positionszinr which" each :piece zcan fit upon the tions of a cylindrical surface;i-'and each: of: said 'i slot-- defining portions offone iwatsh'erbeing."splaced 3 from the adjacent: slot-defining: portions a. of far similar washer by interposed-z spacing :portions' stem having an angle between them that is equal mwhereby rthin filtering-isletsiareprovidedxinsaid to LOB-liS" amoddmnltiple of the angle between. two successiiie'uanns: and: the :pieces being arrangedw onzthezstemia-lternatelyin one-position?and thenv thezothemso=thatz when'zthecentral stem is 'vertlportions of said cylindrical surface? 8. A vfilter stack :as definedfin claim Fl and in: which. the spacing portions ofri'eaohf washer 'lie Y in I the same plane the slot-defining: portions;

cal itheaarms.:.of-ieaeh piceidiedirectly"on toprofgol said spacing portions bein'g.slocate'd atequal dis-' the azmsvof the piece below it; leavinggcontinuous verticalmassagescthroughmhestack;and the gaps between thecends ofiwther'arms ofieachpiecerliea: betweenzandi'orm slots between the rim-like portionszof: the: pieces ii ustvabove' ancl below;

6:::A filten:comprisingaw:stackiofr-similarsfieit elements semimeansextending through: holes in saidielements: n-fors holding them from rotating with-i-respeet= ito'z each other; saidel'ements each Y having arcenter; anreveninumloer. of evenlyilspaced 3 two-mositions: eoncenttic. -.with; but. 'at: an angle to 35 each other,;.the .:angular distancebetweemsaid positionswbeing an qOdCL' :multiple 1 of. the 1 angular. distance; betweenstwo adjacent Y arms r of one of saidaelements; .andrsuccessive elements being arranged on said holdingggmeans indifferent enguo:

lat .positionss Y 'I.-- Asfilter: stack comprising; a. :plurality' of-' superposeel=.-identical washers-all having 5.131182 same tensesaround the "washer-1 and -.being seven-1 in number, and Y said slot-defining portions occupyme only thealtemat'e spaces between 'said spec-"- in'g portions:

PAUL-l-IEFYILER:

REFERENCES CITED v- The following references are Of-iGOOldifi the file of this patent:

UNITED STATES PATENTS Number= Name Date 2,159,196 Babitch May 23, 1939 1,694,939 Heftler:: Dec; 11; 1928' 2,141,436 Harris s Dec- 27," 1938 2,204,592 Heftlers. June lB, 1940" 2,260,899 Hftle'r; Oct; 28, 1941 2,283,629 Heftler May'-19,'1942* 1,641,485 1 Heftler Se'pt.- 6, 1927 FOREIGN PATENTS Number" Country I Date" 327,663- 4 Italy .July 31'1; 1935 

